LJMNvEA. 1 03 



or less intorted, resembling in this respect the form of 

 L. involuta. The present species ranges from Finland, 

 through Sweden, Germany, and France, as far south as 

 the Pyrenees. 



It is rather an active mollusk, and nearly always in 

 motion. Bouchard-Chantereatix says that each of its 

 capsules contains from 30 to 40 eggs. In the young the 

 shell is entirely covered by the pallial fold. 



2. L. INVOLU'TA*, Thompson. 



Limneus involutus, (Harvey) Thomps. in Ann. Nat. Hist. v. p. 22. 

 Limnceus involutus, F. & H. iv. p. 184, pi. cxxii. f. 11. 



BODY unknown as to its external parts, except that the 

 greater part of the shell is covered by the mantle. 



SHELL oval, rather glossy, semitransparent, yellowish- 

 horncolour with a tinge of brown, closely but irregularly 

 striate by the lines of growth, which are stronger towards 

 the suture, often impressed and sometimes constricted by a 

 few spiral grooves in different parts of the shell : epidermis 

 thin : whorls 3-4, convex, the last covering all the rest ex- 

 cept the point of the spire or nucleus : spire flat or slightly 

 concave, with the point upraised and twisted : suture distinct, 

 but not deep : mouth pear-shaped : outer lip thin, slightly 

 reflected : inner lip much spread on the columella : fold 

 narrow and sharp. L. 0-4. B. 0*275. 



HABITAT : A small mountain-lake, and a stream which 

 flows into it, at Cromaglaun near Killarney ; not rare. 

 In one of my specimens, which has the mouth some- 

 what contracted below, a tendency to an umbilical cleft 

 is observable. 



It is strange that no other locality but the one above 

 mentioned has ever been discovered, here or abroad, for 

 this remarkable species. It has some affinity to L. glu- 

 tinosa, and may ultimately prove to be an aberrant form 

 of that species, corresponding with the variety Burnetti 



* Having the spire intorted or sunk. 

 P 



